High sensitivity and low electric power consumption NO2 sensor using SnO2 thin film for smart detector design

Abstract

In this research, SnO2 thin films were prepared by oxidizing the Sn thin films firstly, which was applied for NO2 sensing. The morphology, crystal structure and surface state of the film were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). By optimizing the preparation conditions of SnO2 thin films (i.e., oxidation temperature and thickness of the film), the response to 40 ppb NO2 was increased by 6 times and the response time was shortened by 1.5 times. The sensor shows low detection limit to NO2 at the concentration of 5 ppb at room temperature. It could be found that the high surface area to volume ratio and oxygen vacancy were considered to improving the sensing performance. The NO2 sensor fabricated by this method was available readily, high sensitivity and low power consumption (microwatt magnitude), which has great potential for commercial application.